The gate of the luxury mansion remained firmly shut. It was clear Abdelnasser al-Megrahi had no intention of letting anyone pass. The world would have to accept it was time to let go of his dying brother. A grim saga that began 23 years ago and 2,000 miles away was all but at an end.

A short distance away lay the cancer-ridden body of Abdelbaset al-Megrahi, the man convicted of the 1988 Lockerbie bombing. It was evident on Monday that the campaign for his extradition from Libya was effectively over.

Calls for his re-arrest from US senators, lawyers and relatives of the Lockerbie bombing appeared redundant given Megrahi's condition, apparently close to death, filmed at his mother's house on Sunday and broadcast around the world.

The scoop by CNN prompted a media stampede to the mansion in an upmarket suburb of Tripoli on Monday morning. Two dozen foreign journalists gathered outside in the hope of their own tour of the three-storey, white-walled property decorated with marble cladding, intricate Islamic carvings and green tiled turrets, watched by six security cameras.

More than once a wrought iron door swung open, offering a glimpse of garden, but then closed behind Abdelnasser Megrahi, one of 11 residents. Speaking in Arabic, the 53-year-old former military man politely deflected all requests to see his brother, answered questions and even joked about English football.

Asked about Megrahi's condition, he replied: "He is very sick. The coma came two or three months ago. Sometimes he speaks to his wife or mother, sometimes he is in a coma. His life is in danger now."

He reiterated that his brother had been without proper medical attention for several days. "Medicines have been stolen and we couldn't get them. He did have professional doctors from Italy and Germany and England, but now there is no one, only the doctor here. "

He said the family had emailed a medical report to the Scottish government – with whom Megrahi is obliged to be in regular contact – on Sunday and requested that it send medicine.

Abdelnasser Megrahi also insisted that his brother was not guilty of the Lockerbie bombing. "From day one I believed he was innocent. The case was more political than a crime. There is no actual evidence. The world knows my brother is innocent."

He said Megrahi receives messages of support from Scotland and around the world and criticised the US for continuing to demand his extradition. "He was released by the court. He did not escape. The Americans are being too cruel. They don't even respect him as human being because of his condition."

The American effort now seems increasingly futile. Scottish first minister, Alex Salmond, said recent speculation about Megrahi's disappearance had been "completely inaccurate". Salmond told Sky News: "The only people who have any authority in this matter are the Scottish government, who have jurisdiction in this matter … and the new Libyan transitional council, who are the new duly constituted legal authority in Libya.

"We have never had and don't have any intention of asking for the extradition of Mr Megrahi. It's quite clear from the Libyan transitional council that following their own laws that they'd never any intention of agreeing to such extradition."

Andrew Mitchell, the UK government's secretary for international development, said the question was now moot: "It's clear that many of these matters are now academic as his life is drawing to a close... It's clear from reports today that he has not got much longer to live."

The Obama administration said that the Libyan rebels' National Transitional Council (NTC) had agreed to review Megrahi's case once it has established a fully functioning government.

State department spokeswoman Victoria Nuland said: "This is a guy with blood on his hands, the lives of innocents. Libya itself under Gaddafi made a hero of this guy. Presumably, a new, free, democratic Libya would have a different attitude towards a convicted terrorist. So it is in that spirit the NTC will look at this case."

Calls for Megrahi to be either taken back into Scottish custody or extradited to the US for a fresh trial intensified last week, led by the US Republican Mitt Romney, after it emerged that Scottish officials charged with monitoring him in Libya after his early release from jail had been unable to make contact.

That raised substantial questions about whether Megrahi had breached the terms of his release on licence in August 2009. On Sunday night, East Renfrewshire council and the Scottish government issued a joint statement saying they had finally made contact with Megrahi's family over the weekend.

However, East Renfrewshire officials have admitted to the Guardian that they have not yet spoken to Megrahi in person. Their last contact directly with him was on 8 August. They said they were still trying to talk to him, but confirmed that his dramatically worsening health was making that task far more difficult.

"We are still in the process of re-establishing contact," a council spokesman said on Monday morning. "We have had some contact with the family and we will continue with that." Direct contact is "part of the licence and that is what we are aiming for, if we can do that", he said.

Romney and US relatives claim Megrahi was not properly punished for his alleged role in the Lockerbie atrocity, in which 270 crew, passengers and people on the ground were killed when Pan Am Flight 103 was blown up over the Scottish town in December 1988.

John Bolton, the former US ambassador to the United Nations, said Megrahi should have received the death penalty.

"To me it will be a signal of how serious the rebel government is for good relations with the United States and the west if they hand over Megrahi for trial," he said. "He killed 270 people. He served roughly 10 years in jail before he was released by British authorities. Do the math – that means he served roughly two weeks in prison for every person he killed. Two weeks per murder. That is not nearly enough."

On Monday the NTC backed down from its previous statement that Megrahi would under no circumstances be extradited to Britain. The justice minister, Mohammed al-Alagi, had stated that Megrahi would not be handed back to the west, adding that he had been judged once and would not be judged again. On Monday, however, the minister struck a more ambiguous position, and said Libya was prepared to discuss the issue when other more urgent problems had been sorted out.